Working vehicle

1. A working vehicle comprising:

a cabin which has a roof; and

an outside air inlet portion configured to take outside air that is to be introduced to the cabin, characterized in that the working vehicle further comprises:

a filter device through which the outside air taken from the outside air inlet portion passes, having:

a first filter providing a first filtering level; and

a second filter providing a second filtering level that is a filtering level higher than the first filtering level;

an air conditioning unit to which the outside air having passed through the filter device is supplied; and

a filter changing mechanism having:

a first state to allow the outside air to pass through only the first filter; and

a second state to allow the outside air to pass through at least the second filter among the first filter and the second filter,

the filter changing mechanism being configured to be selectively switched to the first state or the second state,

wherein the filter changing mechanism includes:

a blocking portion configured to block stream of the outside air flowing toward the filter device; and

a movable member configured to move the blocking portion between a first position and a second position,

wherein the first state is established when the blocking portion is moved to the first position,

wherein the second state is established when the blocking portion is moved to the second position,

wherein the roof has an outer roof which constitutes an outer surface of the roof and an inner roof provided inside the outer roof,

wherein the outside air inlet portion is formed in the outer roof,

wherein a first space is formed between the inner roof and a ceiling plate constituting a ceiling of the cabin, and a second space is formed between the inner roof and the outer roof,

wherein the air conditioning unit is arranged in the first space, the filter device is arranged in the second space, and the first space and the second space are communicated with each other through a first opening portion,

wherein the outside air inlet portion includes:

a first outside air inlet portion arranged on one side of the cabin in a width direction of the cabin; and

a second outside air inlet portion arranged on the other side of the cabin in the width direction of the cabin,

wherein the first filter includes:

a one-side filter through which the outside air taken from the first outside air inlet portion passes; and

an other-side filter through which the outside air taken from the second outside air inlet portion passes,

wherein the one-side filter is arranged in a first passage through which the outside air taken from the first outside air inlet portion and flowing toward the air conditioning unit passes,

wherein the other-side filter is arranged in a second passage through which the outside air taken from the second outside air inlet portion and flowing toward the air conditioning unit passes,

wherein the second filter is arranged in an intermediate passage through which the outside air having passed through the first filter toward the air conditioning unit passes,

wherein the intermediate passage is located on a downstream side in a flow direction of the outside air than the first passage and the second passage, and

wherein, under the second state, the outside air having passed through the one-side filter and the other-side filter passes through the second filter.

2. The working vehicle according to claim 1 ,

wherein the filter changing mechanism allows the outside air to pass through both of the first filter and the second filter under the second state.

3. The working vehicle according to claim 2 ,

wherein the first filter is arranged upper than the second filter in a direction of stream of the outside air flowing from the outside air inlet portion toward the air conditioning unit.

4. The working vehicle according to claim 1 ,

wherein the movable member includes:

a support shaft; and

a swing plate configured to be swung about the support shaft to move the blocking portion between the first position and the second position.

5. The working vehicle according to claim 1 ,

wherein the movable member includes:

a rotating shaft; and

a rotating plate configured to be rotated with the rotating shaft to move the blocking portion between the first position and the second position.

6. The working vehicle according to claim 1 , wherein the movable member includes a slide plate configured to be slid to move the blocking portion between the first position and the second position.

7. The working vehicle according to claim 1 ,

wherein the air conditioning unit is arranged on a front portion of the roof,

and wherein the filter device is arranged on a rear portion of the roof.

8. The working vehicle according to claim 1 ,

wherein the air conditioning unit and the filter device are arranged on a rear portion of the roof.

9. The working vehicle according to claim 1 , comprising

an inside-air/outside-air changing mechanism configured to change a ratio between the outside air and air in the cabin in supplied air to the air conditioning unit,

wherein the inside-air/outside-air changing mechanism has a shutter configured to be movable, and

wherein the filter device is arranged upper than the inside-air/outside-air changing mechanism in a direction of stream of the outside air flowing from the outside air inlet portion toward the air conditioning unit.